/*
 * EAP common peer/server definitions
 * Copyright (c) 2004-2012, Jouni Malinen <j@w1.fi>
 *
 * This software may be distributed under the terms of the BSD license.
 * See README for more details.
 */

#include "utils/includes.h"
#include "utils/common.h"

#include "eap_defs.h"
#include "eap_common.h"

//#ifdef CONFIG_WPS

#define WPS_host_to_be16(s)	_htons(s)
#define WPS_be_to_host16(s)	_ntohs(s)
/**
 * eap_hdr_len_valid - Validate EAP header length field
 * @msg: EAP frame (starting with EAP header)
 * @min_payload: Minimum payload length needed
 * Returns: 1 for valid header, 0 for invalid
 *
 * This is a helper function that does minimal validation of EAP messages. The
 * length field is verified to be large enough to include the header and not
 * too large to go beyond the end of the buffer.
 */
// min_payload = 1
int eap_hdr_len_valid(const struct wpabuf *msg, size_t min_payload)
{
	const struct eap_hdr *hdr;
	size_t len;

	if (msg == NULL) {
		wpa_printf(MSG_WARNING, "msg = NULL");
		wpa_printf(MSG_WARNING, "<===eap_hdr_len_valid()");
		return 0;
	}
	hdr = (struct eap_hdr *)wpabuf_head(msg);

	/*
	if (wpabuf_len(msg) < sizeof(*hdr)) {
		wpa_printf(MSG_INFO, "EAP: Too short EAP frame");
		return 0;
	}
	*/
	// get the whole length of eap packet : len = 14   0x20 ?
	len = WPS_be_to_host16(hdr->length);

	if (len < sizeof(*hdr) + min_payload /*|| len > wpabuf_len(msg)*/) {
		wpa_printf(MSG_INFO, "EAP: Invalid EAP length");
		wpa_printf(MSG_INFO, "<===eap_hdr_len_valid()");
		return 0;
	}
	return 1;
}


/**
 * eap_hdr_validate - Validate EAP header
 * @vendor: Expected EAP Vendor-Id (0 = IETF)
 * @eap_type: Expected EAP type number
 * @msg: EAP frame (starting with EAP header)
 * @plen: Pointer to variable to contain the returned payload length
 * Returns: Pointer to EAP payload (after type field), or %NULL on failure
 *
 * This is a helper function for EAP method implementations. This is usually
 * called in the beginning of struct eap_method::process() function to verify
 * that the received EAP request packet has a valid header. This function is
 * able to process both legacy and expanded EAP headers and in most cases, the
 * caller can just use the returned payload pointer (into *plen) for processing
 * the payload regardless of whether the packet used the expanded EAP header or
 * not.
 */
// EAP_VENDOR_WFA(0x00372A), EAP_VENDOR_TYPE_WSC(0x00000001)
const u8 *eap_hdr_validate(int vendor, EapType eap_type,
						   const struct wpabuf *msg, size_t *plen)
{
	const struct eap_hdr *hdr;
	const u8 *pos;
	size_t len;

	if (!eap_hdr_len_valid(msg, 1)) {
		wpa_printf(MSG_INFO, "eap_hdr_len_valid fail!!!");
		return NULL;
	}
	// get the buffer addr and convert to eap header type
	hdr = wpabuf_head(msg);

	// get eap packey total length
	len = WPS_be_to_host16(hdr->length);
	// get the type address of eap packet
	pos = (const u8 *)(hdr + 1);

	if (*pos == EAP_TYPE_EXPANDED) {
		int exp_vendor;
		u32 exp_type;
		if (len < sizeof(*hdr) + 8) {
			wpa_printf(MSG_INFO, "EAP: Invalid expanded EAP length");
			return NULL;
		}
		// get the Vendor-Id address of eap packet
		pos++;
		exp_vendor = WPA_GET_BE24(pos);
		// get the Vendor-Type address of eap packet
		pos += 3;
		exp_type = WPA_GET_BE32(pos);
		// get the Op-Code address of eap packet
		pos += 4;
		// vendor = EAP_VENDOR_WFA(0x00372A),
		// eap_type = EAP_VENDOR_TYPE_WSC(0x00000001)
		if (exp_vendor != vendor || exp_type != (u32) eap_type) {
			wpa_printf(MSG_INFO, "EAP: Invalid expanded frame type");
			return NULL;
		}
		// 8 bytes =  vendor-ID(3) + Type(1) + Vendor-Type(4)
		// report the length of eap packet remainder 570-
		*plen = len - sizeof(*hdr) - 8;
		return pos;
	} else {
		if (vendor != EAP_VENDOR_IETF || *pos != eap_type) {
			//wpa_printf(MSG_INFO, "EAP: Invalid frame type");
			printf("EAP: Invalid frame type, please make sure the EAP method is identical with server side\n");
			return NULL;
		}
		*plen = len - sizeof(*hdr) - 1;

		return pos + 1;
	}
}


/**
 * eap_msg_alloc - Allocate a buffer for an EAP message
 * @vendor: Vendor-Id (0 = IETF)
 * @type: EAP type
 * @payload_len: Payload length in bytes (data after Type)
 * @code: Message Code (EAP_CODE_*)
 * @identifier: Identifier
 * Returns: Pointer to the allocated message buffer or %NULL on error
 *
 * This function can be used to allocate a buffer for an EAP message and fill
 * in the EAP header. This function is automatically using expanded EAP header
 * if the selected Vendor-Id is not IETF. In other words, most EAP methods do
 * not need to separately select which header type to use when using this
 * function to allocate the message buffers. The returned buffer has room for
 * payload_len bytes and has the EAP header and Type field already filled in.
 */
struct wpabuf *eap_msg_alloc(int vendor, EapType type, size_t payload_len,
							 u8 code, u8 identifier)
{
	struct wpabuf *buf;
	struct eap_hdr *hdr;
	size_t len;


	len = sizeof(struct eap_hdr) + (vendor == EAP_VENDOR_IETF ? 1 : 8) + payload_len;

	buf = wpabuf_alloc(len);
	if (buf == NULL) {
		wpa_printf(MSG_WARNING, "buf == NULL!!!");
		return NULL;
	}

	hdr = wpabuf_put(buf, sizeof(*hdr));
	hdr->code = code;
	hdr->identifier = identifier;
	hdr->length = WPS_host_to_be16(len);

	// vendor = EAP_VENDOR_WFA
	if (vendor == EAP_VENDOR_IETF) {
		wpabuf_put_u8(buf, type);
	} else {
		wpabuf_put_u8(buf, EAP_TYPE_EXPANDED);
		wpabuf_put_be24(buf, vendor);
		wpabuf_put_be32(buf, type);
	}

	return buf;
}


/**
 * eap_update_len - Update EAP header length
 * @msg: EAP message from eap_msg_alloc
 *
 * This function updates the length field in the EAP header to match with the
 * current length for the buffer. This allows eap_msg_alloc() to be used to
 * allocate a larger buffer than the exact message length (e.g., if exact
 * message length is not yet known).
 */
void eap_update_len(struct wpabuf *msg)
{
	struct eap_hdr *hdr;
	hdr = wpabuf_mhead(msg);
	if (wpabuf_len(msg) < sizeof(*hdr)) {
		return;
	}
	hdr->length = WPS_host_to_be16(wpabuf_len(msg));
}


/**
 * eap_get_id - Get EAP Identifier from wpabuf
 * @msg: Buffer starting with an EAP header
 * Returns: The Identifier field from the EAP header
 */
u8 eap_get_id(const struct wpabuf *msg)
{
	const struct eap_hdr *eap;

	/*
	if (wpabuf_len(msg) < sizeof(*eap))
		return 0;
	*/
	eap = wpabuf_head(msg);
	return eap->identifier;
}


/**
 * eap_get_id - Get EAP Type from wpabuf
 * @msg: Buffer starting with an EAP header
 * Returns: The EAP Type after the EAP header
 */
EapType eap_get_type(const struct wpabuf *msg)
{
	if (wpabuf_len(msg) < sizeof(struct eap_hdr) + 1) {
		return EAP_TYPE_NONE;
	}

	return (EapType)((const u8 *) wpabuf_head(msg))[sizeof(struct eap_hdr)];
}
//#endif

